A Trial Investigating the Pharmacodynamic Properties of NN1218 in Subjects With Type 1 Diabetes

Inclusion Criteria: * Type 1 diabetes mellitus for more than 12 months * Treated with multiple daily insulin injections or continuous subcutaneous insulin infusion for more than 12 months * Body mass index (BMI) between 18.0-28.0 kg/m\^2 (both inclusive) Exclusion Criteria: * Subject who has donated any blood or plasma in the past month or more than 500 mL within 3 months prior to trial start * Smoker (defined as a subject who is smoking more than 5 cigarettes or the equivalent per day) * Not able or willing to refrain from smoking and use of nicotine substitute products during the inpatient period